70 
SENNA. 
with  acetate  of  lead,  and  decomposed  with  sulphuretted  hydrogen. 
The  acids  thus  obtained  were  compared  in  their  reactions  with 
the  better  known  organic  acids,  but  could  not  be  identified. 
As  I  was  unable  to  devote  to  the  subject  sufiicient  time  for 
complete  examination,  and  the  results  were  not  likely  to  be  of 
pharmaceutical  interest,  I  handed  it  over  to  Dr.  Attfield,  with  a 
request  that  he  would  put  one  of  his  senior  pupils  upon  it,  if  he 
thought  the  subject  worth  following  up.  I  thought  it  not  un- 
likely that  the  inquiry  might  result  in  filling  up  some  gap  in  a 
homologous  series,  and  thus  be  of  scientific  interest.  I  under- 
stand that  the  subject  is  in  the  hands  of  the  senior  Bell  Scholar. 
The  addition  of  diacetate  of  lead  to  filtrate  No.  2,  produced 
a  copious  orange  precipitate,  which,  when  washed  and  difi'used 
through  water,  was  decomposed  with  sulphuretted  hydrogen. 
The  brown  acid  liquid  that  resulted  was  warmed,  neutralized 
with  ammonia  and  evaporated  to  dryness  ;  redissolved  in  water, 
spirit  of  wine  was  added  till  a  precipitate  began  to  form.  This 
precipitate  consisted  of  sulphate  of  ammonia,  in  small  quantity. 
The  liquid  poured  off  from  this  was  treated  with  a  larger  dose  of 
spirit,  when  the  greater  part  of  the  glucoside  acid,  combined  with 
ammonia,  fell  to  the  bottom  in  a  treacly  mass.  This  looked  so 
little  like  an  active  priaciple,  and  was  so  perfectly  devoid  of 
taste  or  smell,  that  1  at  once  jumped  to  the  conclusion  that  it 
could  not  be  the  thing  I  wanted.  I  therefore  passed  it  over,  as 
did  my  forerunner,  Mr.  Rau,  without  administering  one  dose 
even,  and  prosecuted  my  research  in  the  liquid,  from  which,  in 
combination  with  lead,  it  had  been  precipitated.  The  results, 
however,  were  purely  negative. 
I  then  macerated  33  ounces  of  Alexandrian  senna  leaves  (un- 
picked) with  5  pints  of  methylated  spirit,  and,  at  the  end  of  ten 
days,  pressed  and  filtered.  The  spirit,  a  little  water  being  first 
added  to  the  liquid,  was  evaporated,  and  the  resinous  oily  sub- 
stance removed  carefully  from  the  aqueous  fluid  it  overlaid.  It 
was  apparently  destitute  of  medicinal  activity — the  bitterness  of 
the  tincture  being  concentrated  in  the  fluid.  Diacetate  of  lead 
added  to  this  produced  an  orange  precipitate  of  certain  coloring 
matters,  of  no  pharmaceutical  importance.  The  filtrate,  freed 
from  lead,  was  still  bitter,  but  became  less  so  on  evaporation. 
